package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        //1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        //2.判断是关注还是取关
        if(isFollow){
            Boolean hasKey = stringRedisTemplate.hasKey(key);
            if(BooleanUtil.isFalse(hasKey)){
                stringRedisTemplate.opsForSet().add(key,followUserId.toString());
            }
            int count = count(new LambdaQueryWrapper<Follow>()
                    .eq(Follow::getUserId, userId)
                    .eq(Follow::getFollowUserId, followUserId));
            if(count==0){
                save(new Follow().setFollowUserId(followUserId).setUserId(userId));
            }

        }else{
            remove(new LambdaQueryWrapper<Follow>()
                    .eq(Follow::getFollowUserId,followUserId)
                    .eq(Follow::getUserId,userId));

            stringRedisTemplate.opsForSet().remove(key, followUserId.toString());
        }


        return Result.ok();
    }

    @Override
    public Result isFollow(Long followUserId) {
        //1.获取登录用户
        Long userId = UserHolder.getUser().getId();
        String key = "follows:" + userId;
        //2.查询是否关注
        int count = count(new LambdaQueryWrapper<Follow>()
                .eq(Follow::getUserId, userId)
                .eq(Follow::getFollowUserId, followUserId));
        if(count>0 && BooleanUtil.isFalse(stringRedisTemplate.hasKey(key))){
            stringRedisTemplate.opsForSet().add(key,followUserId.toString());
        }
        return Result.ok(count>0);
    }

    @Override
    public Result commonFollow(Long id) {
        //1.当前登录用户
        Long userId = UserHolder.getUser().getId();
        String userKey="follows:"+userId;
        //2.正在查看的用户
        String userViewedKey="follows:"+id;
        //3.求交集
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(userKey, userViewedKey);
        if(intersect==null || intersect.isEmpty()){
            return Result.ok(Collections.emptyList());
        }

        //4.解析共同关注id集合
        List<Long> ids = intersect.stream().map(Long::valueOf).collect(Collectors.toList());

        // 4.查询用户
        List<UserDTO> users = userService.listByIds(ids)
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());
        return Result.ok(users);
    }
}
